Drop down menu bug

Hi, I am using a drop down menu that I built based upon a tute very similar to the kirupa one.

My problem is that because my menu items are positioned just 1px apart, sometimes the submenus do not close if you move the mouse quickly to a menu item above it. It works fine however when moving the mouse quickly to the menu item below.

My menu is vertical and has the submenu items come out to the side. They are all spaced 1px apart, however if you move the mouse too quickly between main menu items, the previous sub menu stays open (as the mouse hasnt rolled over the invisible rolloff area).

Is there a way to get around this if you have your menu’s close together? Having them spaced by 10pixels simply just isnt good enough.

Heres a link to my website to show you whats going on with the menu:
http://www.3amdesign.com.au/lumo/new-website8/